Robert iiadfield



. (ferrum,) chromium,

rucible ried on in the usual way as regards the Bes- UNITED STATES PATENT OFFICE;

ROBERT I-IADFIELD, OF SHEFFIELD, ENGLAND; JOSEPH D. \VEEKS ANCILLARY ADMINISTRATOR OF SAID ROBERT HADFIELD, DECEASED...

stea .ALL'OY.

spncrrxca'rron forming part of Letters Patent m. new, dated September 16,1890.

Application filed August 31, 1885. Serial No. 176,800; (No specimens.) I

To all whom it may concern:

Be it known that I, ROBERT HADFIELD, of Sheflield, in the county of 'York, England, have invented a new and useful Improvement in Steel Alloys; and I do hereby declare the following to act description thereof.

My invention relates to the manufacture of a new and useful metallic, alloy or mixture,

the principal constituents'of which are iron, manganese, and silicon, but which may also contain carbon, as well as other ingredients-such assnlphur and phosphorus-necessarily present in the metal, such alloy having most of the qualities peculiar to ordinary carbon-steel, besides other qualities hereinafter mentioned peculiar to my improved metal. This improved metal I shall speak of as steel, although the presence of carbon, while not injurious, is unessential, the metal depending for its steely qualities chiefly onthe presence of a large percentage of chromium, along with smaller quantities of manganese-and silicon, as hereinafter specified.

To enable others skilled in the art'to manufacture my improved steel, I proceed to describe theprocesses which I employ.

The condition of the iron which forms the basis of my improved steel and from which itis manufactured maybe that of ordinary pig metal, cast-iron, steel, wrougl1t-iron, steel or iron scrap, or amixture of all or any of these, and the process orprocesscs by which the iron or steel is manufactured or reduced or subsequently treated is immaterial, the only necessary requirement being that the iron, before the addition of the chromium, manganese, and silicon, should be substantially decarburized, by which I mean not necessarily entirely devoid of carbon, but that the metal should be or should have been previously decarburized wholly or to a greatextent. Hence my improved process is applicable to the manufacture of steel by means of the Bessemer, open-hearth, or other decarburizing and refining processes or apparatuses or processes, these processes being carsemer, open-hearth, or kindred processes be a full, clear, and exuntil the metal under treatment'is nearly or quite decarbnrized, and then the desired percentages of chromium, manganese, and silimanganese, and

Hitherto in the manufacture of high-class steels it has been considered necessary to employ the best and most costly qualities of iron. I have discovered, however, that if chromium, together with manganese and silicon, is present in sufiicient quantities-say of chromium three-quarters of one per cent.

to seven per cent, of manganese one-tenth one per cent. to twenty per cent, and of silicon one-tenth of one per cent. to five .per cent.the resulting productisa steel of very superior quality, possessing certain marked. characteristics, and I have also discovered that when this is the case the presence of sulphur and phosphorus in the pig or other iron, which forms the basis of the process, to a degree which would materially injure ordinary steel is no disadvantage whatever. There is, however, a practical dilficulty in the production of an alloy or mixture of chromium,

manganese, and silicon with iron, arising from the fact thatin the process of refining and decarburizing metal the chromium, manganese, and siliconpresent are oxidized, so that, especially in the open-hearth, puddling, Bessemer, and other kindred processes, although a large percentage of chromium, manganese, and silicon be present in the charge of iron under treatment, or be added thereto before the carbon has been to a great extent eliminated, or be added thereto previous to the process of reduction, refinement, ordecarburization, the chromium, manganese, and silicon'present in the charge will be to a great extent oxidized and almost entirely eliminated, even after only a partial decarburization, so that if the chromium, manganese, and silicon additions were introduced previously to or during the decarburizing operation they would not remain in the charge or be present in the resulting product. I

. n the manufacture of my improved steel I therefore proceed as follows; If-pigmetal,

too

3 chromium addition chromium, cast, or' pig cast-iron scrap, or a mixtureof these with steel or wrought-iron scrap is used as the basis, the metal is treated inthe ordinary way by the Bessemer, -open-hearth, or other decarburizing and refining process or apparatus until the melted charge is decarburized entirely, substantially, or to a great extent.

I then add the exact amount or percentage of chromium, manganese, amd silicon, the amount of chromium, manganese, and silicon having been previously ascertained in the chromium,

is incorporated with the charge either in thesolid or melted condition. The gross amount of chromium pig or term-chromium to be added will depend on the amount of chromium which it contains, which-will be ascertained beforehand, and also, of course, on the per 'centageof chromiumwhich the resnltin steel.

is desired to contain. .I prefer to use or the iron containing eight to ten per cent. of chro-' minm, forthe reason that such material is comparatively low in carbon, and, being a special product, is moreuniform in it-s quality and constituents.

As an example of manufacture, I add to two thousand pounds decarburized iron six -hnndredand seventy-two pounds of the chrominm pig-iron, herein referred to; also, if necessary, a sufficient quantity of ferr'o-manganese;. but usually the chromi tains sufficient manganese without requiring a separate addition thereof. It is", however, indispensable to have manganese present in my improved steel in suflicient quantity to remove redshortness, remove the slag, and

otherwise improve the steel, so that ifthe chromium alloy does not contain manganese for d'es'not contain sufficient manganese this must be added by means of a separate alloysuch as form-manganese or spiegel-in the usual manner; also, when the chromium alloy does not contain silicon or does not contain sufiicient silicon in addition to the manganese it is indispensable to have silicon present in snflicient quantity in order to remove the gases and produce sound steel.

Thisfl'silicou-may be added by means of a separate silicon alloy-such as silicon pig or cast I 'iron-or' the silicon and manganese may be added by means of one alloy containing both. silicon and manganesesuch as is known by the name of term-manganese silicon --or, if desired, the chromium,-manganese, and sili- 00!! maybe added -bymeans. of one alloy contaiuing manganese,chromium and silicon. I

pig conprefer, however, to add each metal by means of separate alloys, as a more reliable result can be obtained. Such alloys may be added either-in the solid or melted condition, as in the usual way. It is desirable to keep the carbon under one-and a quarter per cent. in'

those steels containing one and a-half per cent. of chromium and upward, on account of the difficulty. which would be experienced in working the ingots when such percentage of carbon is exceeded.

Wher.e'it is desired that the material. produced should have greater toughness combined with closeness of grain, I introduce such an amountof the chromium, manganese, and silicon addition as 'willyield asteel having from one and a half to tw'oand a half per cent. 1? chromium, two-tenths to four-tenths of one per cent. of manganese, and two-tenths to four-tenths of one per cent. of silicon, and

I increase the amount of chromium in varying proportions up to about seven percent. where greater hardness is requisite. As just mentioned, where greateri toughness is requiv site Iv pre'ierto add the manganese and silicon in suilicient. quantities so as to produce in the resulting steel about two-tenths'to four- ,tenths'of one per cent. ofeach metal that is,

one per cent; or. silicon.-

"The amount of manganese and silicon may be variedbetween. the limits indicated in my specification, according to the purposes" for which the steel is required.- Thus where the articles to be produced are of intricate form,

then either the manganese orthe silicon, or both, maybe increased, in order to produce greater freedom from honey-combs, the chromium also being varied. according to the desiredharduesafa's before indicated. After thefchrominm addition -that is, the alloy.

containing chromium, manganese, and sili con, or the. separate alloys of each-has or have been incorporated with the charge it is readyto be run into molds or other. forms, as may be desired. I r

If my improved steel is to be made by the crucible process, the basis of the operation or prime charge being wrought iron or steelscrap, or both combined, the processis then conducted in the usual way, the amount of carbon, if any is'nsed, being preferably less than in the ordinary steel-makingoperations, and the chromium additio'nthat is, the alley containing chromium, manganese, andsilicon, or the separate alloys of eachis or are introduced into the crucible at any stage of the process and becomes or become thoroughly .incorporated with the charge.

My improved steel thus manufactured possesses peculiar hardness, (depending, as before stated, on the amount of chromium, mam.

two-tenths. to'four-tenths of i one. per cent. of manganese and two-tenths to four-tenths of sesscs other peculiar and valuable characteristics, as hereinafter described.

My improved steel may be hardened and tempered either in its castor forged state in the usual way. When it has been run into molds-that is, when the molten material has been used for producing steel castings -although in some cases I then use it as eastwthat is, in its unannealed stateyet when the greatest strength and toughness are required I prefer to anneal such castings in the usual way, and after such annealing the-material possesses a pecular close grain of special density, as well as toughness and hardness. liars turned out; of such castings in my improved material in itsannealcd state, and not forged, rolled, or hammered in any way, tested in a Whitworthmachine, stand tensile strains of fifty to sixtyfive-tons per square inch,whereas ordinary steel castings will not stand more thaln twenty-five to thirty-six tons per square 1110 1.

Notwithstanding the peculiar hardness and closeness of grain from the same material which stands these high tensile strains, shavings have been taken many feet in length, thus showing its toughness, combined with -high tensile strain, which makes itof special advantage and specially adaptedfor a large variety of purposes, such as car wheels, stamp-castings, projectiles, and many other articles. This steel also possesses extraordinary resistance to compr ssion strains. Test pieces turned out of castingsin myiinprove d material and subjected to a compression strain of one hundred tons per square inch in a Whitworth machine only shortened ten per cent. in their length, compared with thirty, forty, and fifty per cent. in pieces turned out of ordinary steel castings and har'nmeredsteel manufactures in the ordinary way.

Having thus described my improved steel claim foriny invention, and desire to secure by Letters Patent, is v 1. As a new article of manufacturasteel containing chromium, together with manganese and silicon,said ingredients being in the proportions of from three-quarters of one per cent. to seven per cent. of chromium, from one-tenth of one per cent. to twenty per cent. of manganese-,and froinone-tenth of one per cent. to five per cent. of silicon, as hereinberm described. I

2. As new article of manufacture, steel containing chromium, together with manganese, said ingredients being in the proportions of from three-quarters of one per cent. to seven per cent. of chromium and from one-tenth of one per cent. to twenty percent. of manganese, as hereinbefore described.

3. As a new article of manufacture, steel containing chromium, together with silicon, said ingredients being in the proportions of from three-quarters of one per cent. toseven one percent. to five per cent. of silicon, as hereinbefore described.

In testimony whereof I-have hereunto set my hand this 3d day of August, A. D. 1885.

ROBERT HAD'FIELD; Witnesses:

R. A. HADFIELD, CHAS, W. Low.

and the method of producing sainc, what I;

per cent. of chromium and from one-tenth of 

